Mare Tranquillitatis

Mare Tranquillitatis on the Moon

Mare Tranquillitatis is a large area on the visible side of the Moon. It is also called the Sea of Tranquillity. It is called a sea because ancient astronomers looked at the Moon and thought they saw seas and oceans on the Moon. Now we know that they are not seas. They are darkened areas on the Moon's surface. They may have been made by ancient volcanoes by things such as leaks and eruptions. Mare Tranquillitatis is just one of the 22 "Seas" and "Oceans" on the Moon.

Naming

In 1651, astronomers Francesco Grimaldi and Giovanni Battista Riccioli named Mare Tranquillitatis in their lunar map.^[1]^[2]

Exploration

Buzz Aldrin salutes the U.S. flag on Mare Tranquillitatis during Apollo 11 in 1969

Map of Mare Tranquillitatis showing the landing sites of Apollo 11, the first manned moon mission, Apollo 17, Apollo 16, and Surveyor 5.

Mare Tranquillitatis was the landing site for the first manned landing on the Moon on July 20, 1969, at 20:18 UTC. Apollo 11 landed at 0°40′27″N 23°28′23″E / 00.67408°N 23.47297°E / 00.67408; 23.47297 (Apollo 11 landing site) .^[3]^[4]

Mare Tranquillitatis Media

Lunar nearside with major maria and craters labelled.
A view of the Apollo 11 landing site at center, facing west, with Maskelyne crater in right foreground
Mare Tranquilitatis AS17-M-1647-1653-1659
Mare Tranquillitatis topographic map (light gray=high, dark gray=low). Generated from LOLA 1024ppd Elevation - Numeric layer with LRO-WAC Shaded Relief layer at 30% opacity overlain.
Gravity map based on GRAIL
Neil Armstrong lands the Apollo 11 Lunar Module Eagle on the Moon at Mare Tranquillitatis, July 20, 1969, creating Tranquility Base. Starts approximately 6200 feet from the surface.
High Sun view of the Mare Tranquillitatis pit crater revealing boulders on an otherwise smooth floor. Image is 400 meters wide, north is up, NAC M126710873R.